A vehicle such as an autonomous or semi-autonomous vehicle can use data from a LIDAR (Light Imaging Detection And Ranging) sensor to aid navigation. LIDAR sensors can be used to generate point cloud data, i.e., a collection of data describing points in three dimensions. Further, an autonomous vehicle may compare its substantially real-time LIDAR point-cloud data to a three-dimensional (3D) map of an area in which the vehicle is operating for navigation within the area. A 3D map of an area can be generated from LIDAR data collected by one or more mapping vehicles that have previously traversed roads in the area for the purpose of obtaining point cloud data for the map. However, using current technology, a problem is that a mapping vehicle may traverse a road segment or the like in an area to be mapped, but collect insufficient data to create the 3D map. When this happens, further data collection is needed, e.g., typically, the road segment or other portion of an area being mapped must be traversed one or more additional times.